Personality is consistently associated with psychopathology across the lifespan. However, little is known of how observed personality dimensions in preschoolers are associated with concurrent or longitudinal symptoms across development. Spectrum, vulnerability, and pathopolasty models theorize how child personality and psychopathology are related across development. The current study tests these three models using observationally coded personality dimensions in a longitudinal sample of preschoolers. A validated 'thin slice' technique was used to code observed Five Factor Model (FFM) personality dimensions of extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience in a clinically enriched preschool sample oversampled for depression (N = 299). Children were followed longitudinally for 9years while assessing dimensional psychological symptoms and global functioning. Longitudinal multilevel models testing the spectrum, or shared underlying factor model, indicated depressive symptoms in adolescence were predicted by higher preschool extraversion and lower agreeableness and conscientiousness, externalizing symptoms were predicted by lower agreeableness and higher neuroticism, and worse global functioning was predicted by higher extraversion and neuroticism, and lower agreeableness and conscientiousness. Some associations held after accounting for the influence of baseline psychological symptoms, indicating support for a vulnerability relationship between personality and later psychopathology. No support was demonstrated for pathoplasty models such that personality did not influence the developmental course or change of psychopathology over time. Findings indicate personality dimensions measured as early as the preschool period prospectively impact psychopathology and functioning across child development, demonstrating support for both a spectrum and vulnerability relationship between youth personality and psychopathology.